Details of the discoveries - including a possible bronze age enclosure and house as well as hundreds of pieces of prehistoric pottery - have only just been made public.
According to Christina O’Regan, project manager and senior archaeologist with the Irish Archaeology Consultancy (IAC), who were contracted by Mouchel (on behalf of Transport NI) to carry out the excavations along the six kilometre route, provisional analysis of the material indicates the area south of Magherafelt was an attractive location for settlement during Neolithic and Bronze Age periods.
“The presence of four existing early medieval sites in the area around the new road and the discovery of post-medieval pottery kilns indicates that the area continued to be an ideal settlement location,” she explained.
“The excavations conducted as part of this development have greatly contributed to the corpus of archaeological data for this part of Northern Ireland.”
The archaeological digs created a lot of interest and speculation in the Magherafelt area when they started in January last year - just ahead of work beginning on the £35 million A31 scheme which is due to open later this year.
The 20-strong team of archaeologists were tasked to undertake a detailed examination of the route.
This involved the excavation of more than 270 test trenches and opening of 15 large areas to examine the underlying subsoil for previously unrecorded archaeological deposits.
These excavations followed on from a non-invasive geophysical survey - used to create maps of sub-surface archaeological features - that had been undertaken by Earthsound Archaeological Geophyics two years earlier.
A total of 11 previously unidentified archeological sites were found across the length of the proposed roadway.
The work took place between March and June last year and, as well as these archaeological sites, a flax mill was subject to a building survey. The mid-nineteenth century mill is located in Leckagh townland, just outside the route of the new Bypass.
The most prominent site was located immediately off the Castledawson Roundabout on a low-lying drumlin, in the townland of Killyneese, Castledawson.
“Archaeological remains consisted of scattered pits, a spread of prehistoric pottery and two post-medieval pottery kilns,” said Christina. “The discovery of the pottery kilns was of particular interest as so few of these have been discovered in Ireland outside of towns and cities.”
More than 1500 sherds of pottery were recovered from the kilns, including some near complete pots.
“It is anticipated that analysis of this assemblage will produce very interesting results,” Christina stressed.
Evidence for prehistoric settlement was encountered across the entire length of the new roadway by the team of archaeologists.
Archaeological sites included circular houses, fulachta fiadh (cooking pits), and gullies.
The most significant site was located in Killyfaddy townland and consisted of a circular gully surrounded by an oval arrangement of postholes with an associated gully.
“This site likely represents the remains of a Bronze Age enclosure and house,” said Christina. “Several fragments of prehistoric pottery were recovered from features associated with the house.”
An unusual stone artefact was also recovered from the entrance to the enclosure - the stone featured a circular hollow on one side and several deep, linear gouges on the other.
It is expected that post-excavation work including sample processing, finds analysis and dating will be carried out to inform the final reports over the coming months.
The prehistoric discoveries at the Magherafelt development follow on from those made during work on the Toome Bypass back in 2003, when evidence for the earliest known signs of human activity in Ireland were found.
Those digs yielded artefacts from the last 9,000 years, taking in the Mesolithic, Neolithic and Bronze Ages right up to the nineteenth century. The material recovered also suggested that the first farms on the island began to appear 200 years before previous estimations.
Last month Environment Minister Mark H Durkan and Regional Development Minister Michelle McIlveen signed an agreement to ensure that archaeological excavations are properly scheduled during the development of new major roads schemes.
Other road construction projects in the past have uncovered previously unknown archaeological sites, resulting in significant financial implications.
In the announcement, Mr Durkan pledged to learn from such experiences. He and Ms McIlveen also signed a Prosperity Agreement between DOE’s Historic Environment Division and DRD’s TransportNI.
The agreement puts in place a framework to ensure that Northern Ireland’s unique and irreplaceable archaeological heritage is properly considered without causing undue disruption to the progression of major road schemes.
It primarily aims to implement a proactive approach to locating, avoiding or scientifically excavating archaeological sites during the early development stages of road schemes.
Mr Durkan said: “This new Prosperity Agreement will see roads and history rhyme. It will allow us better to understand our past while building for the future, at reduced cost.
“We have already piloted our new approach. At much reduced cost and effort, we have found exciting 3,500-4,000 year old Bronze Age remains on the route of the A31 Magherafelt Bypass and an extremely rare and difficult to find 7,000 year old Mesolithic house on the A26 dualling scheme at Glarryford, County Antrim,” said Mr Durkan.
“These are great examples of learning from the past and working together to deliver important benefits for our economy and for our society.”
Commenting on the agreement Michelle McIlveen said: “There is an important balance between ensuring that infrastructure projects are progressed in a sustainable and efficient way while at the same time having minimal impact on our historic environment.
“As we have been moving towards this new agreement, my Department and DoE have been working closely together to find the best ways of locating and preserving our archaeological heritage along the routes of road improvement schemes. This agreement will help build on and strengthen that good work.”